Method and apparatus for marking electric wire

ABSTRACT

An object of the present invention is to provide a method and an apparatus for marking an electric wire at a low cost. An apparatus  1  for marking an electric wire forms a band mark  21  on a part of an outer face  5   a  of the electric wire  3 . The band mark  21  is formed along the entire circumference of the part of the outer face  5   a  of the electric wire  3 . The marking apparatus  1  tightens the electric wire  3  in a state where a tensile force is applied in a longitudinal direction. The marking apparatus  1  includes a nozzle  35  for injecting coloring agent toward an uppermost position  10  of the outer face  5   a  of the electric wire  3 . The nozzle  35  has an open end  42  which is opposed to the electric wire  3  and capable of passing the coloring agent. A straight line L extending between a center C 1  of the open end  42  and a center C 2  of the electric wire  3  lies along a vertical direction.

TECHNICAL FIELD

The present invention relates to a method and an apparatus for markingan electric wire, and more particularly to the method and apparatus formarking an outer face of the electric wire which includes a core wireand an insulating sheath covering the core wire.

BACKGROUND ART

Various types of electronic units are mounted on a motor car as a movingbody. The motor car is provided with wire harnesses for the purpose oftransmitting electric power from a power source, and control signals andso on from a computer or the like to the electronic units. Each of thewire harnesses includes a plurality of electric wires, and a pluralityof connectors to be attached to ends of the electric wires.

The electric wire is composed of an electrically conductive core wireand a sheath made of insulating synthetic resin for covering the corewire. The electric wire is a so-called sheathed wire. The connector isprovided with electrically conductive terminal metals and an insulatingconnector housing. The terminal metals are fixed to the ends of theelectric wires so as to be electrically connected with the core wires ofthe electric wires. The connector housing is formed in a box-like shapeand contains the terminal metals.

On occasion of assembling the above described wire harness, the electricwires are cut into a predetermined length as a first step, and then, theterminal metals are fixed to the ends of the electric wires. A pluralityof the electric wires are connected to each other, according tonecessity. Thereafter, the terminal metals are inserted into theconnector housing. The wire harness can be assembled in this manner.

It is necessary to identify the electric wires of the above describedwire harness with respect to a size of the core wire, material of thesheath (the material may vary depending on presence of heat resistingproperty or so), an object for use, etc. The object for use means, forexample, an air bag, an ABS (Antilock Brake System), a powertransmitting system, and a system of the motor car in which the electricwires for transmitting control signals including vehicle speedinformation etc. are employed.

Conventionally, the electric wire for the wire harness has been providedwith a ring-like band mark in a part of its outer face along an entirecircumference thereof, in order to identify the objects for use(systems), as described above. For this purpose, it has beenconventionally accustomed that when synthetic resin is extruded to formthe sheath around the core wire, coloring agent of a desired color isadmixed to the synthetic resin. Then, another coloring agent which hasdifferent color from the aforesaid coloring agent is applied to a partof the synthetic resin which has covered the core wire, that is, theouter face of the sheath, along an entire circumference thereof. In thismanner, the part of the outer face of the sheath has been colored alongthe entire circumference thereof to form the band mark on the electricwire.

In a process for forming the band mark on the above described electricwire, the coloring agent has been applied to the outer face of theelectric wire by blowing it together with a pressurized air, as anaerosol. On this occasion, a plurality of nozzles have been employed forblowing the coloring agents, and these nozzles have been arranged alonga circumferential direction of the electric wire at a substantiallyequal interval.

A plurality of the nozzles have been conventionally employed asdescribed above. Therefore, there has been such a problem that anapparatus for marking the electric wire has become large-sized requiringa larger space for installation, and that a production cost for theapparatus has been increased. This would incur a rise of the overallcost for marking the electric wire.

In view of the above, an object of the present invention is to provide amethod and an apparatus for marking an electric wire which can beoffered at a low cost.

DISCLOSURE OF THE INVENTION

In order to solve the above described problem and attain the object,there is provided, according to the present invention, a method formarking an electric wire which includes an electrically conductive corewire and an insulating sheath by injecting a certain amount of coloringagent to an outer face of the electric wire, wherein the electric wireis tightened in a state where a tensile force is applied in alongitudinal direction, and the coloring agent is injected from an upperside of the electric wire to an upper part of the outer face of theelectric wire.

According to the above described aspect of the invention, the electricwire is tightened with the tensile force, and therefore, positionaldisplacement of the electric wire can be prevented. As the results, thecoloring agent which has been injected toward the upper part of theouter face of the electric wire can be reliably adhered to this upperpart. The coloring agent which has been adhered to the upper part of theelectric wire moves downward by gravity in a state adhered to the outerface of the electric wire.

For this reason, by providing only one means or mechanism for injectingthe coloring agent, it is possible to adhere the coloring agent to apart of the outer face of the electric wire along the entirecircumference thereof.

In the method for marking an electric wire according to the inventor,the coloring agent is injected toward an area including the uppermostposition of the outer face of the electric wire.

According to the above described aspect, the coloring agent is injectedtoward an area located at the uppermost position of the electric wire.Therefore, the coloring agent which has been adhered to the electricwire reliably moves downward by gravity in a state adhered to the outerface of the electric wire. For this reason, by providing only one meansor mechanism for injecting the coloring agent, it is possible to adherethe coloring agent to a part of the outer face of the electric wirealong the entire circumference thereof.

In the method for marking an electric wire according to the inventor,the coloring agent is injected through an open end which is opposed tothe outer face of the electric wire, and a line extending between acenter of the open end and a center of the electric wire lies along avertical direction.

According to the above described aspect, the line extending between thecenter of the open end and the center of the electric wire lies along avertical direction. Therefore, the open end is positioned right abovethe electric wire. As the results, the coloring agent is reliablyadhered to the uppermost position of the electric wire. Therefore, thecoloring agent which has been adhered to the electric wire movesdownward more reliably by gravity in a state adhered to the outer faceof the electric wire. For this reason, by providing only one means ormechanism for injecting the coloring agent, it is possible to adhere thecoloring agent to a part of the outer face of the electric wire alongthe entire circumference thereof more reliably. It is to be noted thatthe vertical direction is the direction of the gravity.

According to the present invention, there is further provided anapparatus for marking an electric wire which includes an electricallyconductive core wire and an insulating sheath, by injecting a certainamount of coloring agent to an outer face of the electric wire, theapparatus comprising tightening means for tightening the electric wirein a state where a tensile force is applied in a longitudinal direction,and injecting means provided above the electric wire which is tightenedby the tightening means, and adapted to inject the coloring agent,wherein the injecting means injects the coloring agent from an upperside of the electric wire to an upper part of the outer face of theelectric wire.

According to the above described aspect, the electric wire is tightenedby the tightening means, and therefore, positional displacement of theelectric wire can be prevented. The injecting means is positioned abovethe electric wire and injects the coloring agent toward the upper partof the electric wire. As the results, the coloring agent can be reliablyadhered to the upper part of the electric wire. The coloring agent whichhas been adhered to the upper part of the electric wire moves downwardby gravity in a state adhered to the outer face of the electric wire.For this reason, by providing only one injecting means, it is possibleto adhere the coloring agent to a part of the outer face of the electricwire along the entire circumference thereof.

In the apparatus for marking an electric wire according to theinvention, the coloring agent is injected toward an area including theuppermost position of the outer face of the electric wire.

According to the above described aspect, the injecting means injects thecoloring agent toward an area located at the uppermost position of theelectric wire. Therefore, the coloring agent which has been adhered tothe electric wire reliably moves downward by gravity in a state adheredto the outer face of the electric wire. For this reason, by providingonly one means or mechanism for injecting the coloring agent, it ispossible to adhere the coloring agent to a part of the outer face of theelectric wire along the entire circumference thereof.

In the apparatus for marking an electric wire according to theinvention, the injecting means includes an open end which is opposed tothe outer face of the electric wire, whereby the coloring agent isinjected through the open end, and a line extending between a center ofthe open end and a center of the electric wire lies along a verticaldirection.

According to the above described aspect, the line extending between thecenter of the open end of the injecting means and the center of theelectric wire lies along a vertical direction. Therefore, the open endof the injecting means is positioned right above the electric wire. Asthe results, the coloring agent can be reliably adhered to the uppermostposition of the electric wire. Therefore, the coloring agent which hasbeen adhered to the electric wire moves downward by gravity in a stateadhered to the outer face of the electric wire, more reliably. For thisreason, by providing only one means or mechanism for injecting thecoloring agent, it is possible to adhere the coloring agent to a part ofthe outer face of the electric wire along the entire circumferencethereof.

The above described coloring agent is liquid material consisting ofcolor material (organic substance for industrial purpose) which isdissolved or dispersed in water or other solvent. As the organicsubstance, the coloring agent includes dyes and pigments which aregenerally composites of the organic substances. The dyes may be used asthe pigments, or the pigments may be used as the dyes according tocases. As more specific examples, the coloring agent in the claims meansboth coloring liquid and paint. The coloring liquid means the dye whichis dissolved or dispersed in the solvent, while the paint means thepigment which is dispersed in dispersion liquid. Therefore, when thecoloring liquid has been adhered to the outer face of the sheath, thedye will be infiltrated into the sheath. On the other hand, when thepaint has been adhered to the outer face of the sheath, the pigment willnot be infiltrated into the sheath, but simply adhered to the outerface. Therefore, the method for marking the outer face of the sheathincludes both dyeing a part of the outer face of the sheath with thedye, and applying the pigment to the part of the outer face of thesheath.

Preferably, the aforesaid solvent and dispersion liquid is compatiblewith the synthetic resin which forms the sheath. In this case, the dyecan be reliably infiltrated into the sheath, and the pigment can bereliably adhered to the outer face of the sheath.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram showing a structure of an apparatus formarking an electric wire according to a first embodiment of the presentinvention.

FIG. 2 is a perspective view of the electric wire which has been markedby the apparatus for marking an electric wire as shown in FIG. 1.

FIG. 3 is a plan view of the electric wire as seen in a direction of anarrow mark III in FIG. 2.

FIG. 4 is a side view of the electric wire as seen in a direction of anarrow mark IV in FIG. 3.

FIG. 5 is a bottom view of the electric wire as seen in a direction ofan arrow mark V in FIG. 4.

FIG. 6 is a sectional view taken along a line VI-VI in FIG. 1.

FIG. 7 is an explanatory diagram showing a structure of an apparatus formarking an electric wire according to a second embodiment of the presentinvention.

FIG. 8 is an explanatory view showing a modified example of positionalrelation between a nozzle of the apparatus for marking an electric wireaccording to the present invention and the electric wire.

FIG. 9 is a bottom view showing a modified example of the electric wireas shown in FIG. 5.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, a first embodiment of the present invention will be describedreferring to FIGS. 1 to 6.

An apparatus 1 for marking an electric wire (hereinafter simply referredto as “a marking apparatus”) in FIG. 1 is employed for forming aring-like band mark 21 on a part of an outer face 5 a of a sheath 5 ofan electric wire 3, along an entire circumference thereof, as shown inFIGS. 2 to 5. In short, the marking apparatus 1 marks the outer face 5 aof the sheath 5 of the electric wire 3.

The electric wire 3 is one component of a wire harness to be arranged inan automobile as a moving body. The electric wire 3 includes, as shownin FIG. 2, a core wire 4 having electrical conductivity, and theinsulating sheath 5. The core wire 4 is formed of a plurality ofmaterial wires 6 twisted together. The material wires 6 composing thecore wire 4 are made of electrically conductive metal. The sheath 5 isformed of, for example, synthetic resin such as polyvinyl chloride(PVC). Since the sheath 5 covers the core wire 4, the outer face 5 a ofthe sheath 5 can be deemed as an outer face of the electric wire 3.

The sheath 5 has a single color P. In order to give the single color Pto the outer face 5 a of the electric wire 3, coloring agent having adesired color may be admixed to the synthetic resin which will form thesheath 5, or the synthetic resin may not be mixed with the coloringagent so that the color of the synthetic resin itself may constitute thesingle color P. In case where the color of the synthetic resin itself isthe single color P with no coloring agent mixed to the synthetic resin,the outer face 5 a of the sheath, that is, the outer face of theelectric wire 3 is called as colorless. In this manner, the term“colorless” means that the outer face 5 a of the electric wire 3 has thecolor of the synthetic resin itself without mixing the coloring agentinto the synthetic resin.

The ring-like band mark 21 as shown in FIGS. 2 to 5 is formed in a partof the outer face 5 a of the electric wire 3. The band mark 21 has acolor B (represented by paralleled diagonal lines in FIGS. 2 to 5). Thecolor B is different from the above described single color P of theouter face 5 a of the sheath 5.

The band mark 21 is formed on a part of the outer face 5 a of the sheath5 along the entire circumference of the electric wire 3. As shown inFIG. 3, the band mark 21 has the largest width H1 in a longitudinaldirection of the electric wire 3, at the uppermost position 10 in FIG.2, in a part of the outer face 5 a of the sheath 5. On the other hand,as shown in FIG. 5, the band mark 21 has the smallest width H2 in alongitudinal direction of the electric wire 3, at the lowermost position11 in FIG. 2, in the part of the outer face 5 a of the sheath 5.

As shown in FIG. 4, the band mark 21 has a width H3 which is larger thanthe width H2 and smaller than the width H1 in a longitudinal directionof the electric wire 3, at lateral positions 12 in FIG. 2, in the partof the outer face 5 a of the sheath 5. In this manner, the band mark 21is formed to have the widths H1, H3, H2 in a longitudinal direction(along an axis Q represented by an alternate long and short dash line inFIG. 2) of the electric wire 3 which become gradually narrower fromabove to below in the part of the outer face 5 a of the electric wire 3.

A plurality of the electric wires 3 having the above described structureare provided with connectors or so at their ends, and bundled into oneto form the above described wire harness. The connectors are coupled toconnectors of the electronic units of various types in the automobile orthe like, and the wire harness, that is, a group of the electric wires 3transmit various signals or electric power to the electronic units.

Moreover, by changing the color B of the above described band mark 21into various different colors, the electric wires 3 can be identifiedfrom one another. The color B of the band mark 21 is used foridentifying the electric wires 3 with respect to types, systems, etc. Inother words, the color B of the band mark 21 represents an object foruse of the electric wire 3 of the wire harness, and at the same time,enables the object for use to be identified.

The marking apparatus 1 is an apparatus for forming the above describedband mark 21 on a part of the outer face 5 a of the electric wire 3. Themarking apparatus 1 includes, as shown in FIG. 1, a feeding reel 30 asfeeding means, and a take-up reel 31 as take-up means, a brake 39 astightening means, an injecting unit 32, an encoder 33 as detectingmeans, and a control device 34. The feeding reel 30 and the take-up reel31 are rotatably installed with a space from each other on a floor of afactory or the like.

The electric wire 3 is wound around the feeding reel 30, and fed to thetake-up reel 31. The take-up reel 31 takes up the electric wire 3 whichhas been fed from the feeding reel 30. The take-up reel 31 is providedwith a motor 40, and rotates in a direction of an arrow mark Y1 in FIG.1 by driving force of the motor 40. The feeding reel 30 is not providedwith a motor, and rotates in a direction of an arrow mark Y2 in FIG. 1by being pulled by the electric wire 3, when the take-up reel 31 takesup the electric wire 3 while rotating in the direction of the arrow markY1 in FIG. 1. It is to be noted that the directions of the arrow mark Y1and the arrow mark Y2 are in the same direction.

When the above described motor 40 is driven to rotate and the take-upreel 31 rotates in the direction of the arrow mark Y1, the electric wire3 moves in a longitudinal direction thereof, that is, along an axis Q ofthe electric wire 3 which is represented by an arrow mark K in FIG. 1.

The brake 39 is fixed to both the feeding reel 30 and the floor. Whenthe feeding reel 30 rotates, the brake 39 applies a friction force tothe feeding reel 30 so as to hinder the rotation of the feeding reel 30.For this reason, the brake 39 tends to decrease number of the rotationof the feeding reel 30 as compared with number of the rotation of thetake-up real 31. Consequently, a tensile force in a longitudinaldirection will be applied to the electric wire 3 which is stretchedbetween the feeding reel 30 and the take-up reel 31. In other words, thebrake 39 keeps the electric wire 3 tightened in a state where thetensile force is applied in a longitudinal direction.

The injection unit 32 is provided between the feeding reel 30 and thetake-up reel 31 as shown in FIG. 1. The injection unit 32 includes anozzle 35 as injecting means, and a valve 36.

The nozzle 35 is arranged above the electric wire 3 which is movingalong the direction of the arrow mark K by means of the feeding reel 30and the take-up reel 31. The nozzle 35 has a nozzle hole 41 for allowingcoloring agent T (See FIG. 1) to pass therethrough. An open end 42 ofthe nozzle hole 41 is opposed to the electric wire 3 which is movingalong the direction of the arrow mark K by means of the feeding reel 30and the take-up reel 31.

Thus, the nozzle 35 is provided with the open end 42 which is opposed tothe electric wire 3. The coloring agent T is supplied from a coloringagent supply source 37 into the nozzle hole 41 of the nozzle 35. Thecoloring agent T has the above described color B.

As shown in FIG. 6, a straight line L (represented by an alternate longand short dash line in FIG. 6) extending between a center C1 of the openend 42 of the nozzle 35 and a center C2 of the electric wire 3 liesalong a vertical direction. The vertical direction represents adirection of gravity. Therefore, the open end 42 of the nozzle 35 ispositioned right above the electric wire 3.

The valve 36 is connected to the nozzle 35, and a pressurized air supplysource 38 is further connected to the valve 36. The pressurized airsupply source 38 supplies pressurized air to the nozzle 35 by way of thevalve 36. When the valve 36 is opened, the coloring agent T in thenozzle hole 41 of the nozzle 35 is injected through the open end 42toward the uppermost position 10 of the outer face 5 a of the electricwire 3, with an aid of the pressurized air supplied from the pressurizedair supply source 38.

For this purpose, the nozzle 35 injects (injects in drops) the coloringagent T toward an area 10 a including the uppermost position 10 of theouter face 5 a of the electric wire 3. In short, the nozzle 35 injects(injects in drops) the coloring agent T toward an upper half 13 of theelectric wire 3, thereby allowing the coloring agent T to be adhered tothe aforesaid area 10 a including the uppermost position 10 of the outerface 5 a of the electric wire 3.

When the valve 36 is closed, injection (injection in drops) of thecoloring agent T from the nozzle 35 is stopped. As the injection unit 32has the above described structure, the valve 36 is kept open for apredetermined period according to signals from the control device 34,thereby to inject (inject in drops) a determined amount of the coloringagent T to the outer face 5 a of the electric wire 3.

The above described coloring agent T is liquid material consisting ofcolor material (organic substance for industrial purpose) dissolved ordispersed in water or other solvent. As the organic substance, thecoloring agent T includes dyes and pigments which are generallycomposites of the organic substances. The dyes may be used as thepigments, or the pigments may be used as the dyes according to cases.More specifically, the coloring agent T is in a form of coloring liquidor paint. The coloring liquid means the dye dissolved or dispersed inthe solvent, while the paint means the pigment dispersed in dispersionliquid. Therefore, when the coloring liquid has been adhered to theouter face 5 a of the electric wire 3, the dye will be infiltrated intothe sheath 5. On the other hand, when the paint has been adhered to theouter face 5 a of the electric wire 3, the pigment will not beinfiltrated into the sheath 5, but simply adhered to the outer face 5 a.

In other words, the injection unit 32 serves to dye a part of the outerface 5 a of the electric wire with the dye, or alternatively, to applythe pigment to the part of the outer face 5 a of the electric wire 3.Therefore, a method for marking the outer face 5 a of the electric wireincludes both dyeing a part of the outer face 5 a of the electric wirewith the dye, and applying the pigment to the part of the outer face 5 aof the electric wire 3.

Preferably, the aforesaid solvent and dispersion liquid is compatiblewith the synthetic resin which forms the sheath 5. In this case, the dyecan be reliably infiltrated into the sheath 5, and the pigment can bereliably adhered to the outer face 5 a of the sheath 5.

The phrase “injection in drops” means that a certain amount of thecoloring agent in a liquid form is injected with force, in a form ofdrops, from the nozzle 35 of the injection unit 32 toward the outer face5 a of the electric wire 3. Accordingly, in the marking apparatus 1 ofthe present embodiment, the nozzle 35 of the injection unit 32 injectswith force a certain amount of the coloring agent which has been in aform of liquid and changed into a form of drops toward the outer face 5a of the electric wire 3.

The encoder 33 has a rotor 43 as shown in FIG. 1. The rotor 43 canrotate around an axis of rotation. An outer peripheral face of the rotor43 is in contact with the outer face 5 a of the electric wire 3 which isforced to move along the direction of the arrow mark K by means of apair of the reels 30, 31. When the core wire 4, that is, the electricwire 3 runs (moves) in the direction of the arrow mark K, the rotor 43rotates. In short, the rotor 43 rotates around its axis of rotationalong with the running (moving) of the core wire 4, that is, theelectric wire 3 along the direction of the arrow mark K. It is apparentthat number of the rotation of the rotor 43 is in direct proportion to amoving distance of the electric wire 3 along the direction of the arrowmark K.

The encoder 33 is connected to the control device 34. When the rotor 43rotates by a predetermined angle, the encoder 33 outputs pulse signalsto the control device 34. More specifically, the encoder 33 outputsinformation corresponding to moving velocity of the core wire 4, thatis, the electric wire 3 along the direction of the arrow mark K. In thismanner, the encoder 33 measures the information corresponding to themoving velocity of the electric wire 3, and outputs the information tothe control device 34. By thus outputting the pulse signals, the encoder33 detects a determined position of the electric wire 3. This determinedposition is desirably such a position that the nozzle 35 of theinjection unit 32 may start to inject the coloring agent T, in order tomark the electric wire 3 while it is moving. Usually, the encoder 33outputs pulse signals according to a moving amount of the electric wire3 by friction between the electric wire 3 and the rotor 43 of theencoder 33. However, in case where the moving amount is inconsistentwith number of the pulse signals, depending on condition of the outerface 5 a of the electric wire 3, it would be possible to obtain theinformation of the moving velocity in other places, and to feedback theinformation for comparative calculation.

The control device 34 is a computer provided with known RAM, ROM, CPU,and so on. The control device 34 interconnects the motor 40 of thetake-up reel 31, the encoder 33, the valve 36, the pressurized airsupply source 38, and so on, thereby to control all the operations ofthe marking apparatus 1. An opening degree when the valve 36 is opened,a duration of the opening, and pressure of the pressurized air suppliedto the valve 36 from the pressurized air supply source 38 are stored ina memory of the control device 34. Preferably, the above describedopening degree, duration of the opening, and pressure are such valuesthat the coloring agent T injected from the nozzle 35 can be adhered tothe entire circumference of a part of the outer face 5 a of the electricwire 3. The control device 34 opens and closes the valve 36 according tothe information from the encoder 33 about the moving velocity, in short,the predetermined position of the electric wire 3.

When the marking apparatus 1 having the above described structure formsthe band mark 21 on the outer face 5 a of the electric wire 3, in otherwords, marks the outer face 5 a of the electric wire 3, an end of theelectric wire 3 which has been spooled around the feeding reel 30 iswound around the take-up reel 31 as a first step. Then, the motor 40 isdriven to rotate the take-up reel 31 in the direction of the arrow markY1, and also the feeding reel 30 in the direction of the arrow mark Y2.In this manner, the electric wire 3 moves from the feeding reel 30 tothe take-up reel 31, and tightened in a state applied with a tensileforce, because the friction force is applied to the feeding reel 30 bymeans of the brake 39.

Thereafter, the pulse signals in a predetermined order are inputted fromthe encoder 33 into the control device 34. The control device 34 opensthe valve 36 at the opening degree which has been stored, and keeps thevalve 36 open for the duration of opening which has been stored. On thisoccasion, the control device 34 supplies the pressurized air from thepressurized air supply source 38 to the nozzle 35 with the pressurestored in the memory. Then, a determined amount of the coloring agent Tis injected (injected in drops) toward the outer face 5 a of theelectric wire 3 through the open end 42 of the nozzle hole 41 in thenozzle 35 of the injection unit 32.

The coloring agent T in liquid form is adhered to the area 10 aincluding the uppermost position 10 of the outer face 5 a of theelectric wire 3. In other words, the coloring agent T in liquid form isadhered to the upper half 13 of the electric wire 3. The coloring agentT which has been adhered to the outer face 5 a of the electric wire 3moves downward by gravity along the outer face 5 a of the electric wire3, before the solvent or the dispersion liquid is vaporized. After thecoloring agent T has been adhered up to the lower area of the outer face5 a, the solvent or the dispersion liquid will be vaporized. Then, thedye or the pigment in the coloring agent T will remain on the outer face5 a, and the above described band mark 21 will be formed on the outerface 5 a of the electric wire 3. Thus, the electric wire 3 having theabove described structure can be obtained. In this manner, the band mark21 will be formed in a form of a colored ring on a part of the outerface 5 a of the electric wire 3 along the entire circumference thereof.

According to the present embodiment, the electric wire 3 is tightened bymeans of the brake 39, and therefore, positional displacement of theelectric wire 3 can be prevented. The nozzle 35 of the injection unit 32is located above the electric wire 3, and injects (injects in drops) thecoloring agent T in liquid form toward the area 10 a including theuppermost position 10 of the electric wire 3. As the results, the nozzle35 of the injection unit 32 can reliably adhere the coloring agent T inliquid form to the area 10 a including the uppermost position 10 of theelectric wire 3. The coloring agent T which has been adhered to the area10 a including the uppermost position 10 of the electric wire 3 movesdownward by gravity in a state adhered to the outer face 5 a of theelectric wire 3.

For this reason, by providing only one nozzle 35 of the injection unit32, it is possible to adhere the coloring agent T in liquid form to apart of the outer face 5 a of the electric wire 3 along the entirecircumference thereof. Therefore, the band mark 21 can be formed byproviding only one nozzle 35 of the injection unit 32, and so, themarking apparatus 1 for the electric wire can be manufactured at a lowcost, and the overall cost for marking the electric wire can bedecreased.

In addition, the straight line L extending between the center C1 of theopen end 42 of the nozzle hole 41 in the nozzle 35 and the center C2 ofthe electric wire 3 lies along a vertical direction. Therefore, the openend 42 of the nozzle 35 of the injection unit 32 is positioned rightabove the electric wire 3. As the results, the nozzle 35 of theinjection unit 32 can reliably adhere the coloring agent T to theuppermost position of the electric wire 3.

For this reason, by providing only one nozzle 35 of the injection unit32, it is possible to more reliably adhere the coloring agent T to apart of the outer face 5 a of the electric wire 3 along the entirecircumference thereof. Therefore, the band mark 21 can be formed byproviding only one nozzle 35 of the injection unit 32, and so, themarking apparatus 1 for the electric wire can be manufactured at a lowcost, and the overall cost for marking the electric wire can bedecreased.

Now, referring to FIG. 7, an apparatus 1 for marking an electric wireaccording to a second embodiment of the present invention will bedescribed. The same components as in the first embodiment will bedenoted with the same reference numerals and their description will beomitted.

In the present embodiment, the feeding reel 30 is provided with a motor44 as the tightening means. The motor 44 rotates the feeding reel 30 inthe direction of the arrow mark Y2. The motor 44 tends to rotate thefeeding reel 30 with less number of rotation than the number of rotationof the motor 40 which is mounted on the take-up reel 31 as describedabove.

Because the number of rotation of the motor 40 mounted on the take-upreel 31 is more than the number of rotation of the motor 44 mounted onthe feeding reel 30, the electric wire 3 is always pulled toward thetake-up reel 31. As the results, the feeding reel 30 rotates in thedirection of the arrow mark Y2 with the same number of rotation as thetake-up reel 31.

In this manner, the motor 44 which is mounted on the feeding reel 30tends to rotate the feeding reel 30 with the number of rotation lessthan the number of rotation of the motor 40 which is mounted on thetake-up reel 31, and accordingly, the electric wire 3 is tightened in astate applied with a tensile force in a longitudinal direction. In thisembodiment too, the straight line L extending between the center C1 ofthe open end 42 of the nozzle hole 41 in the nozzle 35 and the center C2of the electric wire 3 lies along a vertical direction.

In the marking apparatus 1 in the present embodiment, the motors 40 and44 are driven to rotate the reels 31 and 30 in the directions of thearrow marks Y1 and Y2, enabling the electric wire 3 to be tightened in astate applied with the tensile force in the longitudinal direction.Then, according to the signals from the encoder 33, the control device34 controls the valve 36 and the pressurized air supply source 38 toinject (inject in drops) the determined amount of the coloring agent Tin liquid form to the area 10 a including the uppermost position 10 ofthe electric wire 3. The coloring agent T in liquid form which has beenadhered moves downward by gravity along the outer face 5 a of theelectric wire 3, before the solvent or dispersion liquid is vaporized,and after the solvent or the dispersion liquid has been vaporized, theband mark 21 is formed on the outer face 5 a of the electric wire 3.

According to this embodiment, the electric wire 3 is tightened in astate applied with the tensile force in the same manner as in the firstembodiment, and therefore, positional displacement of the electric wire3 can be prevented. The nozzle 35 of the injection unit 32 injects thecoloring agent T toward the area 10 a including the uppermost position10 of the electric wire 3. In addition, the straight line L extendingbetween the center C1 of the open end 42 of the nozzle hole 41 in thenozzle 35 and the center C2 of the electric wire 3 lies along a verticaldirection. For this reason, by providing only one nozzle 35 of theinjection unit 32, it is possible to form the band mark 21 on a part ofthe outer face 5 a of the electric wire 3 along the entire circumferencethereof. Therefore, the marking apparatus 1 can be manufactured at a lowcost, and the overall cost for marking the electric wire 3 can bedecreased.

In the above described first and second embodiments, the straight line Lextending between the center C1 of the open end 42 of the nozzle hole 41in the nozzle 35 and the center C2 of the electric wire 3 lies along avertical direction, and the nozzle 35 is positioned right above theelectric wire 3. However, in the present invention, it would besufficient that the nozzle 35 is positioned even a little higher thanthe electric wire 3. In other words, the nozzle 35 need not necessarilybe positioned right above the electric wire 3, provided that the nozzle35 is anyway positioned higher than the electric wire 3.

In this case, it is desirable that the nozzle 35 is arranged at such aposition that the injected coloring agent T can be adhered to the area10 a including the uppermost position 10 of the electric wire 3, asshown in FIG. 8. In FIG. 8, a trajectory of the coloring agent Tinjected from the nozzle 35 is represented by a two dot chain line R. Inthis case too, the band mark 21 can be formed by employing the singlenozzle 35, and the cost for the marking apparatus 1 can be reduced.

Moreover, the coloring agent T injected from the nozzle 35 need notnecessarily be adhered to the uppermost position 10. It would besufficient that the coloring agent T is adhered to the outer face 5 apositioned in the upper half 13 in cross section of the electric wire 3.It is to be noted that the upper part of the electric wire 3 describedin the claims means the upper half 13 which is positioned above thecenter of the electric wire in cross section.

Further, the band mark 21 is formed on a part of the outer face 5 a ofthe electric wire 3 along the entire circumference thereof, in the abovedescribed first and second embodiments. However, according to thepresent invention, as shown in FIG. 9, the coloring agent T which hasbeen spread up to the lower part of the electric wire 3 need not jointogether, but there may be formed a zone where the coloring agent T doesnot exist. The description that the coloring agent T is adhered to theentire circumference or substantially entire circumference of the outerface 5 a of the electric wire 3 means both that the coloring agent T isadhered to the outer face 5 a along the entire circumference thereof,and that there is formed the zone where the coloring agent T does notexist.

In the first and second embodiments as described above, only oneinjection unit 32 is provided. However, according to the presentinvention, it is apparent that a plurality of injection units 32 may beprovided, and a plurality of band marks 21 may be formed on the outerface 5 a, by employing a plurality of coloring agents, in short, with aplurality of colors.

Further, in the first and second embodiments as described above, thecontrol device 34 includes a computer provided with ROM, RAM, CPU, etc.However, according to the present invention, the control device 34 mayinclude a known digital circuit or the like. In this case, it isnecessary to employ a circuit for counting the pulse signals from theaforesaid encoder 33, and a circuit for deciding whether the aforesaidvalve 36 is to be opened or closed when the pulse signal of a certainnumber has been inputted.

It would be also apparent that the marking apparatus 1 in the first andsecond embodiments can be mounted on various types of working machineswhich are employed in a wire harness assembling process, such as anelectric wire cutting device in which a determined length of theelectric wire 3 is fed and cut.

Moreover, the present invention has been described as applied to theelectric wire 3 which forms the wire harness to be arranged in anautomobile in the first and second embodiments. However, it is apparentthat the electric wire 3 may be employed not only in the automobile butalso in various types of electronic units such as a portable computer,or various types of electric machines, according to the presentinvention.

Further, the coloring liquid and paint may includes acrylic paint, ink(dye, pigment), UV ink, etc. according to the present invention.

INDUSTRIAL APPLICABILITY

As fully described herein above, according to the present invention, theelectric wire is tightened with the tensile force, and therefore,positional displacement of the electric wire can be prevented. As theresults, the coloring agent which has been injected toward the upperpart of the outer face of the electric wire can be reliably adhered tothis upper part of the electric wire. The coloring agent which has beenadhered to the upper part of the electric wire reliably moves downwardby gravity in a state adhered to the outer face of the electric wire.Therefore, by providing only one means or mechanism for injecting thecoloring agent, it is possible to adhere the coloring agent to a part ofthe outer face of the electric wire along entire circumference thereof.Accordingly, the band mark can be formed by providing only one means ormechanism for injecting the coloring agent, and so, the overall cost formarking the electric wire can be decreased.

According to the present invention, the coloring agent is injectedtoward an area located at the uppermost position of the electric wire.Therefore, the coloring agent which has been adhered to the electricwire reliably moves downward by gravity in a state adhered to the outerface of the electric wire. Therefore, by providing only one means ormechanism for injecting the coloring agent, it is possible to adhere thecoloring agent reliably to a part of the outer face of the electric wirealong entire circumference thereof. Accordingly, the band mark can beformed by providing only one means or mechanism for injecting thecoloring agent, and so, the overall cost for marking the electric wirecan be decreased.

According to the present invention, the line extending between thecenter of the open end and the center of the electric wire lies along avertical direction. Therefore, the open end is positioned right abovethe electric wire. As the results, the coloring agent is reliablyadhered to the uppermost position of the electric wire. Therefore, thecoloring agent which has been adhered to the electric wire movesdownward more reliably by gravity in a state adhered to the outer faceof the electric wire. Therefore, by providing only one means ormechanism for injecting the coloring agent, it is possible to adhere thecoloring agent more reliably to a part of the outer face of the electricwire along entire circumference thereof. Accordingly, the band mark canbe formed by providing only one means or mechanism for injecting thecoloring agent, and so, the overall cost for marking the electric wirecan be decreased.

According to the present invention, the electric wire is tightened bythe tightening means. Therefore, positional displacement of the electricwire can be prevented. The injecting means is positioned above theelectric wire and injects the coloring agent toward the upper part ofthe electric wire. As the results, the coloring agent can be reliablyadhered to the upper part of the electric wire. The coloring agent whichhas been adhered to the upper part of the electric wire moves downwardby gravity in a state adhered to the outer face of the electric wire.For this reason, by providing only one injecting means, it is possibleto adhere the coloring agent to a part of the outer face of the electricwire along the entire circumference thereof. Accordingly, because theband mark can be formed by providing only one means for injecting thecoloring agent, the marking apparatus for the electric wire can bemanufactured at a low cost, and the overall cost for marking theelectric wire can be decreased.

According to the present invention, the injecting means injects thecoloring agent toward an area located at the uppermost position of theelectric wire. Therefore, the coloring agent which has been adhered tothe electric wire reliably moves downward by gravity in a state adheredto the outer face of the electric wire. For this reason, by providingonly one means for injecting the coloring agent, it is possible toadhere the coloring agent to a part of the outer face of the electricwire along the entire circumference thereof. Accordingly, because theband mark can be formed by providing only one means for injecting thecoloring agent, the marking apparatus for the electric wire can bemanufactured at a low cost, and the overall cost for marking theelectric wire can be decreased.

According to the present invention, the line extending between thecenter of the open end of the injecting means and the center of theelectric wire lies along a vertical direction. Therefore, the open endof the injecting means is positioned right above the electric wire. Asthe results, the coloring agent can be reliably adhered to the uppermostposition of the electric wire. Therefore, the coloring agent which hasbeen adhered to the electric wire moves downward by gravity in a stateadhered to the outer face of the electric wire, more reliably. For thisreason, by providing only one means for injecting the coloring agent, itis possible to adhere the coloring agent to a part of the outer face ofthe electric wire along the entire circumference thereof. Accordingly,because the band mark can be formed by providing only one means forinjecting the coloring agent the marking apparatus for the electric wirecan be manufactured at a low cost, and the overall cost for marking theelectric wire can be decreased.

1. A method for marking an electric wire which includes an electricallyconductive core wire and an insulating sheath, by injecting a certainamount of coloring agent to an outer face of said electric wire, whereinsaid electric wire is tightened in a state where a tensile force isapplied in a longitudinal direction, and said coloring agent is injectedin drop form from an upper side of said electric wire onto an upper partof the outer face of said electric wire to form a band as a mark as aring on the electric wire, with the drop contacting the uppermostportion of the upper part and moving downwardly by gravity along theouter face to form the band, which gradually becomes narrower from aboveto below the outer face.
 2. The method for marking an electric wire asclaimed in claim 1, wherein said coloring agent is injected through anopen end of a nozzle which is opposed to the outer face of said electricwire, and a line extending between a center of said open end and acenter of said electric wire lies along a vertical direction.
 3. Amethod for marking an electric wire, which includes an electricallyconductive core wire and an insulating sheath, by injecting a certainamount of coloring agent to an outer face of said electric wire, whereinsaid electric wire is tightened in a state where a tensile force isapplied in a longitudinal direction, and said coloring agent is injectedin drop form from an upper side of said electric wire onto an upper partof the outer face of said electric wire to form a band as a mark on theelectric wire, with the drop contacting the uppermost portion of theupper part and moving downwardly by gravity along the outer face to formthe band, and wherein an uppermost portion of the mark has a widthlarger than a width of the mark at a lowermost portion of the mark, in alongitudinal direction of the electric wire.